Foundations Of Threads And Multithreading Concepts Practice Tests

Question 1

A process has a memory footprint of 50 MB. If 4 threads are created within this process, and each thread requires an additional 5 MB of stack space, what is the approximate total memory footprint of the multithreaded process?

Accepted Answer

C. 70 MB

Answer

A. 50 MB

Answer

B. 55 MB

Answer

D. 200 MB

Question 2

In a multithreaded process, each thread has its own dedicated address space, separate from other threads within the same process.

Accepted Answer

True

Answer

False

Question 3

A web server handles 100 requests per second using a single-threaded process. The average request processing time is 10 ms. If the server is converted to a multithreaded process with 10 threads, ideally, what would be the new request processing capacity per second, assuming no overhead?

Accepted Answer

C. 1000 requests per second

Answer

A. 10 requests per second

Answer

B. 100 requests per second

Answer

D. 10000 requests per second

Question 4

A computationally intensive task takes 60 seconds to complete on a single-core processor using a single thread. Assuming perfect parallelism and no overhead, how long would it take to complete the same task on a quad-core processor using four threads?

Accepted Answer

15 seconds

Question 5

Which of the following are potential advantages of using multithreading in an application?

Answer

A. Improved responsiveness

Answer

B. Increased resource sharing

Answer

C. Enhanced scalability

Answer

D. Reduced memory usage

Question 6

A program processes data in a pipeline fashion: Thread A reads data from disk, Thread B processes the data, and Thread C writes the processed data to another disk. If Thread A takes 5 seconds, Thread B takes 10 seconds, and Thread C takes 5 seconds, what is the approximate throughput (in terms of data processed per second) of this pipeline after it reaches a steady state, assuming each thread operates concurrently?

Accepted Answer

B. Limited by the slowest thread (Thread B)

Answer

A. Limited by the sum of all thread times (20 seconds)

Answer

C. Limited by the fastest thread (Thread A)

Answer

D. Limited by the average thread time (6.67 seconds)

Question 7

A process has 5 user threads. If the system uses the many-to-one threading model and one thread makes a blocking system call, what happens to the other threads?

Accepted Answer

All threads in the process are blocked.

Answer

Only the blocking thread is blocked.

Answer

The process continues to run with the remaining threads.

Answer

The kernel creates a new thread to handle the remaining user threads.

Question 8

User threads are managed directly by the operating system kernel.

Accepted Answer

True

Answer

False

Question 9

In a one-to-one threading model, a process creates 10 user threads. How many kernel threads will be created?

Accepted Answer

10

Answer

1

Answer

5

Answer

The number depends on the system load.

Question 10

Explain how the many-to-many threading model addresses the limitations of both the many-to-one and one-to-one models.

Accepted Answer

The many-to-many model maps multiple user-level threads to multiple kernel threads. This avoids the blocking issue of the many-to-one model and the overhead of creating too many kernel threads in the one-to-one model.

Question 11

Which of the following are advantages of using kernel threads?

Answer

Can leverage multicore/multiprocessor architectures.

Answer

Faster context switching compared to user threads.

Answer

The OS considers both process and thread scheduling.

Answer

No system calls are required for thread management.

Question 12

Which threading model is also known as a hybrid approach?

Accepted Answer

Two-Level (Hybrid) Model

Answer

Many-to-One Model

Answer

One-to-One Model

Answer

Many-to-Many Model

Question 13

Describe a scenario where using user threads would be more advantageous than using kernel threads.

Accepted Answer

User threads are more advantageous when the application requires very fast context switching and can tolerate the limitation of not fully utilizing multicore processors. For example, in a simulation environment where numerous lightweight tasks need to be rapidly switched, user threads can provide better performance due to the absence of kernel involvement.

Question 14

In Java, which method is essential for a thread created by implementing the `Runnable` interface to execute its task?

Accepted Answer

B. run()

Answer

A. start()

Answer

C. execute()

Answer

D. process()

Question 15

Write a Java code snippet that creates a thread using the `Runnable` interface and starts it. Assume a class `MyTask` that implements `Runnable`.

Accepted Answer

MyTask task = new MyTask();
Thread thread = new Thread(task);
thread.start();

Question 16

When extending the `Thread` class in Java, you must override the `start()` method to define the thread's execution logic.

Accepted Answer

False

Answer

True

Question 17

In Java, what is the primary difference between implementing the `Runnable` interface and extending the `Thread` class for creating threads?

Accepted Answer

C. Implementing `Runnable` allows a class to extend another class, while extending `Thread` does not.

Answer

A. Extending `Thread` is more memory-efficient.

Answer

B. Implementing `Runnable` is faster.

Answer

D. Extending `Thread` is the preferred method for multithreading.

Question 18

In C using Pthreads, write the function call to create a new thread that executes the function `my_thread` with argument `arg`, storing the thread ID in `thread_id`.

Accepted Answer

pthread_create(&thread_id, NULL, my_thread, arg);

Question 19

Which of the following functions are part of the Pthreads library in C?

Answer

A. pthread_create

Answer

B. pthread_join

Answer

C. pthread_exit

Answer

D. thread_start

Question 20

In a multithreaded socket server in C, if the server receives 10 client connection requests simultaneously, and each client request takes 0.5 seconds to process, what is the approximate total processing time if the server uses 5 threads, assuming perfect load balancing?

Accepted Answer

B. 1.0 seconds

Answer

A. 0.5 seconds

Answer

C. 2.5 seconds

Answer

D. 5.0 seconds

Foundations Of Threads And Multithreading Concepts Practice Tests

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Foundations of Threads and Multithreading Concepts

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